Rolling mill

ABSTRACT

This invention relates to a rolling mill and, more particularly, to the construction of a cantilever-supported roll having means for disconnecting the roll drive in the event of an overload in the mill.

United States Patent Hermann J Leitner Langenield, Germany Nov. 12, 1969Dec. 21, 19,71 1

SIEMAG Siegener Maschlnenbau (11.111.11.1 1. llilchenbaclt-Dahlbruch,Germany Nov. 26, 19 68 Germany Inventor Appl. No. Filed 1 PatentedAssignee Priority ROLLING MILL 10 Claims, 6 Drawing Figs.

u.s.c1 72/249, 72/431 1111. c1 1321b 35/14 Field oiSearch 72/237, 249,199,431; 285/2, 3,4; 287/5201; 29/1 10,115,121,12$;83/S43;192/150;143/32 [56] References Cited UNITED STATESPATENTS 1,183,620 5/1916 Biggert 83/543 3,491,571 1/1970 O'Brien 72/244FORElGN PATENTS 1,224,974 6/1960 France 83/543 Primary Examiner-CharlesW. Lanham Assistant Examiner-B. J. Ollila Anomey-Norman S. BlodgettABSTRACT: This invention relates to a rolling mill and, moreparticularly, to the construction of a cantilever-supported roll havingmeans for disconnecting the roll drive in the event of an overload inthe mill.

PATENTEB 05021 197a 352 3 5 SHEET 1 BF 2 INVENTOR.

HERMANN J. LEITNER ATTO NEY ROLLING Mitt In the construction of rollingmills, particularly those for rolling rod which subsequently is drawninto wire, it is com mon practice to mount the rolls on shafts whichextend from the housing in a cantilevered manner. Such cantileveredmounting of rolls offers anumber of advantages, including thepossibility of changing rolls readily. In the construction of suchcantilevered rolling'mills, it is common practice to make the rollersinthe form of rings which have the roll pass grooves formed on the outerperipheral surface. These rings are detachably mounted on the shaft andheld in place by clamping them in the axial direction. Such a rollingmill design is shown in German Pat. No. 329,839; furthermore, in GermanPat. Nos. 21,979 and 690,134, it has been suggested that the groovedrolls be mounted on the shaft in such a manner as to provide forchanging the grooves. Along the same line, US. Pat. Nos. 1,289,602;1,494,313 1; 1,528,392; and 2,342,159 show similar designs. French Pat.No. 1,481,623 shows the concept of an overhung grooved rolling mill usedin a rod mill. German Pat. No. 490,185, as well as GermanAuslegeschriften No. 1,140,535 and No. 1,146,467 shows that it is old tointerlock the roll and the drive shaft by means of pins.

However, all of these-prior art rolling mill rolls have the disadvantagethat, when they are used in a rolling mill, it is possible to achievesafe operation in the presence of possible excess rolling forces androlling momentum during the rolling operations only when they areconnected with a rolling mill drive having a predetermined breakingpoint which corresponds to the maximum permissible rolling force ormaximum permissible rolling momentum. Drive shafts having such apredetermined breaking point are well known, as shown in German Pat. No.1,222,000. The main disadvantage of such a drive arrangement with apredetermined breaking point is that a relatively large mass is locatedbetween the safety elements and the roll which is acted upon during therolling operation. The excessive force that takes part in an accident oroverload has to work through this mass before it gets to the point wherethe safety element is operative. These and other difficultiesexperienced with the prior art devices have been obviated in a novelmanner by the present invention.

It is, therefore, an outstanding object of the invention to provide arolling mill having a cantilever-mounted roll, wherein means is providedbetween the roll and the mounting shaft for disconnecting the roll fromthe drive when an excessive couple is experienced by the roll.

Another object of this invention is the provision of a rolling millhaving a roll which incorporates an overload device.

A further object of the present invention is the provision of anoverload apparatus for use with a rolling mill in which the overloaddevice can be changed at the same time that the roll is changed.

It is another object of the instant invention to provide an overloadapparatus for use in a rolling mill, which apparatus is simple andrugged in construction, inexpensive to manufacture, and capable of along life of useful service with a minimum of maintenance.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rollingmill having a housing, having a shaft mounted for rotation in thehousing, and having an annular roll with a peripheral roll pass groovemounted on the shaft for rotation therewith. A locking element extendsaxially between the roll and the shaft, the element having a portioncapable of breaking at a predetermined axial stress. An interengagingmeans extends between the roll and the shaft and is spaced from thelocking element, which means is operative when the roll is subjected toa couple about its axis to subject the locking. element to axial stress.

BRIEF DESCRIPTION OF THE DRAWINGS I The character of the invention,however, may be best understood by reference to one of itsstructuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a vertical sectional view of a rolling mill embodying theprinciples of the present invention,

FIG. 2 is a horizontal sectional view of a portion of the ap' paratus,

FIG. 3 is a vertical sectional view of a modified form of the invention,

FIG. 4 is a horizontal sectional view of the apparatus shown in FIG. 3,

FIG. 5 is a vertical sectional view of a still further modified form ofthe invention, and

FIG. 6 is a transverse vertical view of the apparatus shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention consistsof a rolling mill, especially a rod mill in which a driving shaft isprovided with a cantileversupported grooved roll. This roll is clampedin the axial direction and is interlockedwith the drive shaft to turnwith it by means of pins. A safety device is provided to ensure againstexcessive rolling force and excessive: rolling momentum during therolling operation. This device acts directly on the rolling mill rolland is quite sensitive, because of the small movable mass involved. Insolving this problem, the invention suggests that the axial clampingelement be in the form of a bolt which has a predetermined breakingpoint and which is lined up with roll axis. Locking pins between thedrive shaft and the roll engage surfaces which are sloped at an angle tothe roll axis. Therefore, if the couple on the roll becomes too greatbecause of an obstruction, then, in accordance with the invention, thepins between the drive :shaft and the roll act like a screw. By actingin this way, the clamping bolt is placed under stress in the directionof the roll axis. In case the couple exceeds predetermined limits (whichdepend on the actual material cross section present at the predeterminedbreaking point, on the tensile strength of the material in the anchorbolt, and on the slope of the wedge surfaces), then the predeterminedbreaking point is reached and the bolt breaks, thus separating the rollring. In accordance with the invention, it is practical to make thebreaking point of the anchor bolt in the same plane as the groove of theroll and in the form of a groove in the bolt. In this way, thepredetermined breaking point is always in the area of the largestrolling force acting on the roll. After the anchor bolt breaks, theinvention provides for each replacement in the form of a detachablepulloff Sleeve for the roll, which sleeve has a center bore for looseinsertion of the anchor bolt. The shaft has a shoulder against which thehead of the anchor bolt is held in the axial direction. It is possible,in accordance with the invention, to arrange several of the safety pinsequally distributed around the rolls circumference. It has been foundespecially useful and of advantage to arrange the pins in the radialdirection and resting on one side in a semicircular-shaped recess on aface of the shaft facing toward the roll. On the other side, these pinsengage wedge-shaped or V-shaped grooves formed on a radial surface ofthe roll facing toward the face of the shaft. Other designs are possiblewithin the framework of the invention to secure against excessiverolling force and excess rolling momentum. For instance, balls can beused in place of the pins, which balls are positioned in one side withina cup located on the face of the shaft and on the other side arepositioned within a groove having a slope in the direction of the rollmotion and located in a facing surface of the roll. Another designinvolves wedge-shaped cams formed directly on the shaft which engagecorresponding wedge-shaped recesses on the facing side of the roll.

Referring first to FIG. 1, it can be seen that the rolling mill 1 isprovided with a shaft 3 rotated by a drive spindle 2. A tongue-and-groove arrangement 4 locks the spindle and shaft together. Inorder to secure the shaft 3 against movement in the axial direction onthe spindle 2, a screw 5 is located in the shaft 3 which engages acorresponding bore 6 in the spindle 2. The shaft is supported in aplainbearing 7 in a roll housing 8 and is provided with a centeringsocket 9 on the front or working side of the roll housing.

The centering socket 9 on the shaft 3 has an axial hole 10 and has asupporting shoulder or counterbore 11 facing toward the spindle 2.Through the hole 10 passes an anchoring bolt 12 whose head 13 rests inthe counterbore.

A ringlike roll 14 is formed with a roll pass groove 15 and has acentering flange 16 which extends into a suitable recess in thecentering socket 9 of the shaft 3. The anchor bolt 12 extends in theaxial direction through the roll 14 and a hole 17 formed in a clampingplate 18 which is positioned on the outwardly facing side of the roll14. The roll is clamped by means of the clamping plate 18 and by nuts 19on the bolt 12 which press the assemblage against the centering sleeveor shaft 3.

To lock the roll against turning on the shaft 3, carrier pins 20 arearranged in equal spacing about the roll circumference. These pins arearranged on the shaft 3 in such a way that they rest insemicylindrically shaped recesses 21 in the vicinity of the centeringflange 16 of the roll, as can be clearly seen in FIG. 2. The free sideof each pin 20 engages a V-shaped groove 22 on the roll, these grooveshaving wedge-shaped surfaces 23. The wedge-shaped surfaces 23 of thegrooves 22 combine with the free part of the pin 20 and a breakinggroove 24 of the bolt 12 to form safety element insuring againstexcessive roll forces and excessive roll momentum. In the case of anaccident, the rolling momentum will exceed the permissible value and arelative turning of the roll 14 occurs relative to the shaft 3.Consequently, the wedge-shaped surfaces 23 of the grooves 22 try toclimb spirally on the circumference of the pin 20. When this occurs, theroll is displaced in the axial direction and acts on the breaking groove24 of the bolt 12. When the roll momentum exceeds the stress limit ofthe material cross section of the breaking groove, the bolt isoverstressed and the roll separates from the shaft 3 and from the drivespindle 2. It is particularly important that the breaking groove of thebolt be positioned in line with the groove 15 of the roll, because thepredetermined breaking point does not only act during the time that anexcessive roll torque is arrived at, but is also effective whenexcessive roll forces occur and acts to separate the roll on suchoccasions also.

In FIGS. 3 and 4, a roll 44 is also arranged in a cantilever method in arolling mill 31, but differs from the construction shown in FIG. 1mainly by the use of balls 55 in place of the pins. These bails restwithin corresponding cups 56 formed on a centering socket portion 39 ofa shaft 33. On the front side of a centering shoulder 46 of the roll 44are arranged grooves 57 having a slope in the direction of the motion ofthe roll. The rolling mill roll 44 is mounted on the shaft 33 which, inturn, is driven by a drive spindle 32 through an interconnecting means34. A bearing 37 carries the spindle 33 in a housing 38. An anchor bolt42 has its head 43 engaging a counterbore 41 and extends through a hole40 in the shaft. A reduced portion or groove 54 formed on the boltprovides for breakage on occasion and nuts 49 operate with a clampingplate or sleeve 48 to hold the roll in place.

in FIGS. 5 and 6, the rolling mill 61 consists of a drive spindle 62connected to a shaft 63 by means of a keyway 64. The shaft 63 is mountedin a bearing 67 in a rolling mill housing 68 and is provided with acentering socket 69 on which is mounted a ringlike roll 74 having a rollpass groove 75. A conical recess 76 on the roll engages a similarlyshaped male cone on the shaft 63. An anchoring bolt 72 having aweakening groove 84 has its head 73 carried in a counterbore 71 in theshaft 63 and extends through a bore 70 axially of the shaft. Nuts 79operate on the bolt 72 to hold the roll in place by cooperating with aconically shaped clamping plate 80, which engages a suitable conicalrecess on the outer face of the roll. The shaft 63 is provided with afinger 88 havinga sloping surface which engages a recess 89 in the rollhaving a similarly shaped surface 91.

Under the normal load of the rolling mill, the cam fingers 88 and therecesses 89 act together as locking means between the roll and theshaft. However, when the roll torque is increased to a point in excessof the normal load by any kind of interference or accident, a relativeturning movement is created between the roll 74 and the shaft 63. Forcedby this relative movement, the wedge-shaped areas 91 of the recess 89are moved upwardly in a spiral manner along the wedge-shaped areas 90 ofthe cams or fingers 88. This forces the roll in the axial direction.When such action takes place in the axial direction, the groove 84 oftheanchor bolt 72 is placed under stress and, if the stress is in excessof a predetermined value, the bolt will be broken. The roller 74 is thenseparated from the shaft 63 and, correspondingly, the rolling mill issafe against overloading. The broken anchor bolt may be readilyreplaced, it being only necessary to remove the shaft 63 from the end ofthe drive spindle 62. 7

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereoflt is not, however, desired to confine the invention to the exactform herein shown and described, but it is desired to include all suchas properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent is:

1. A rolling mill, comprising a. a housing,

b. a shaft mounted for rotation in the housing,

c. an annular roll having an outwardly directed groove and mounted onthe shaft for rotation therewith,

d. a clamping element extending axially between the roll and shaft, theelement having a portion capable of breaking at a predetermined axialstress, and

e. interengaging means extending between the roll and shaft spaced fromthe clamping element and operative, when the roll is subjected to aforce couple, to subject the locking element to axial stress.

2. A rolling mill as recited in claim 1, wherein the shaft is mounted inthe housing with one end extending therefrom in cantilever fashion,wherein the roll is fastened coaxially to the said one end of the shaftby the clamping element, and wherein the clamping element is an axialbolt which has a reduced portion which will break under the saidpredetermined stress, the reduced portion and the roll groove lying inthe same general plane perpendicular to the roll axis.

3. A rolling mill as recited in claim 2, wherein the shaft is providedwith a removable clamping plate engageable with the roll to hold it inplace on the shaft, wherein the plate has a central bore for receivingthe bolt, and wherein the shaft has an axial bore to receive the bolt,the shaft bore having a counterbore to receive a head of the bolt and afurther counterbore to receive a drive spindle.

4. A rolling mill as recited in claim 2, wherein the interengaging meansconsists of several cam elements associated with one of the roll andshaft and engaging a cam surface on the other of the roll and shaft, thecam element cooperating with the cam surface to produce a slightrelative axial movement between the shaft and roll when the said coupleis applied to the roll.

5. A rolling mill as recited in claim 4, wherein the cam element is aradially extending pin residing in a semicylindrical notch in the shaftand the cam surface is a V-shaped notch in the roll.

6. A rolling mill as recited in claim 4, wherein the cam element is aball located in a semicylindrical notch in the shaft and the cam surfaceis a V-shaped notch in a roll.

7. A rolling mill as recited in claim 4, wherein the cam element is afinger extending axially of the shaft and having a surface inclined tothe axis of the shaft and the cam surface is formed on a recess in theroll, which surface is inclined to the axis at the same angle as thesaid surface of the cam element.

8. A rolling mill as recited in claim 4, wherein the shaft is providedwith a radial surface which is parallel to and spaced from acorresponding radial surface on the roll, and wherein the interengagingmeans extends between these two surfaces.

9. A rolling mill as recited in claim 3, wherein the roll is provided onboth sides with axially extending annular flanges, wherein the shaft isprovided with an annular recess to receive one of the flanges, andwherein the clamping plate is also provided with an annular recess toreceive the other flange.

10. A rolling mill as recited in claim 3, wherein the roll is providedon both sides with coaxial conical recesses, wherein the shaft isprovided with a male conical surface received in one of the recesses,and wherein the clamping plate is provided with a male conical surfacereceived in the other of the said recesses.

1. A rolling mill, comprising a. a housing, b. a shaft mounted forrotation in the housing, c. an annular roll having an outwardly directedgroove and mounted on the shaft for rotation therewith, d. a clampingelement extending axially between the roll and shaft, the element havinga portion capable of breaking at a predetermined axial stress, and e.interengaging means extending between the roll and shaft spaced from theclamping element and operative, when the roll is subjected to a forcecouple, to subject the locking element to axial stress.
 2. A rollingmill as recited in claim 1, wherein the shaft is mounted in the housingwith one end extending therefrom in cantilever fashion, wherein the rollis fastened coaxially to the said one end of the shaft by the clampingelement, and wherein the clamping element is an axial bolt which has areduced portion which will break under the said predetermined stress,the reduced portion and the roll groove lying in the same general planeperpendicular to the roll axis.
 3. A rolling mill as recited in claim 2,wherein the shaft is provided with a removable clamping plate engageablewith the roll to hold it in place on the shaft, wherein the plate has acentral bore for receiving the bolt, and wherein the shaft has an axialbore to receive the bolt, the shaft bore having a counterbore to receivea head of the bolt and a further counterbore to receive a drive spindle.4. A rolling mill as recited in claim 2, wherein the interengaging meansconsists of several cam elements associated with one of the roll andshaft and engaging a cam surface on the other of the roll and shaft, thecam element cooperating with the cam surface to produce a slightrelative axial movement between the shaft and roll when the said coupleis applied to the roll.
 5. A rolling mill as recited in claim 4, whereinthe cam element is a radially extending pin residing in asemicylindrical notch in the shaft and the cam surface is a V-shapednotch in the roll.
 6. A rolling mill as recited in claim 4, wherein thecam element is a ball located in a semicylindrical notch in the shaftand the cam surface is a V-shaped notch in a roll.
 7. A rolling mill asrecited in claim 4, wherein the cam element is a finger extendingaxially of the shaft and having a surface inclined to the axis of theshaft and the cam surface is formed on a recess in the roll, whichsurface is inclined to the axis at the same angle as the said surface ofthe cam element.
 8. A rolling mill as recited in claim 4, wherein theshaft is provided with a radial surface which is parallel to and spacedfrom a corresponding radial surface on the roll, and wherein theinterengaging means extends between these two surfaces.
 9. A rollingmill as recited in claim 3, wherein the roll is provided on both sideswith axially extending annular flanges, wherein the shaft is providedwith an annular recess to receive one of the flanges, and wherein theclamping plate is also provided with an annular recess to receive theother flange.
 10. A rolling mill as recited in claim 3, wherein the rollis provided on both sides with coaxial conical recesses, wherein theshaft is provided with a male conical surface received in one of therecesses, and wherein the clamping plate is provided with a male conicalsurface received in the other of the said recesses.